Catalyst system

ABSTRACT

An improved catalyst system for selectively preparing monohalogenated olefins, e.g. vinyl chloride, wherein a mixture containing an olefin, hydrogen halide and source of oxygen is reacted with a catalyst system containing a palladium halide, e.g., palladium chloride; a ferric halide, e.g. ferric chloride and an alkali metal halide wherein the alkali metal is selected from the group consisting of sodium and potassium, e.g. sodium chloride. The reaction is conducted at a temperature in the range of between 350* and 650*. The halide moiety of the catalysts employed are identical and correspond to the halogenated hydrocarbon produced. Monohalogenated olefins such as vinyl chloride are important and valuable commercial products, particularly as precursors for polymeric materials.

Ail L 22. 19 2 5. J pan:

United States Patent Dugan 1 51 June 13, 1972 CATALYST SYSTEM [72]Inventor: John J. Dugan, Sarnia, Ontario, Canada [73] Assignee: EssoResearch and Engineering Company [22] Filed: Feb. 19, 1969 1211 Appl.No.: 800,713

521 U.S. c1 ..26o/6s6 R, 260/648 R, 260/651 R,

260/654 A, 260/659 A 511 111:. c1 ..C07c 21/06 58 Field 61 Search..260/659 A, 656, 662

[56] References Cited UNITED STATES PATENTS 2,838,577 6/1958 Cook et al...260/656 2,957,924 10/1960 Heiskell et al.... ....260/659 A X 3,214,48210/1965 Caropresio... .....260/659 A 3,267,161 8/1966 Ukaji et a1..260/659 A FOREIGN PATENTS OR APPLICATIONS eyes 968,152 8/1964 GreatBritain ..260/656 Primary Examiner-Howard T. Mars Attorney-Chasan andSinnock and J. E. Luecke [57] ABSTRACT I of the catalysts employed areidentical and correspond to the halogenated hydrocarbon produced.Monohalogenated olefins such as vinyl chloride are important andvaluable commercial products, particularly as precursors for polymericmaterials.

6 Claims, No Drawings CATALYST SYSTEM BACKGROUND OF THE INVENTION Thisinvention relates to the manufacture of halogenated hydrocarbons. Moreparticularly, this invention relates to an improved catalyst system forthe selective formation of monohalogenated olefins, e.g. vinyl chloride.More specifically, this invention relates to a novel catalyst systemwhich consists of a palladium metal halide, ferric halide and an alkalimetal halide, the alkali metal selected from the group consisting ofsodium and potassium, in order to selectively form the monohalogenatedolefin, e.g. vinyl chloride, at good conversion levels. The catalytichalide moieties employed are identical and correspond to the halogenatedhydrocarbon produced. Thus, if vinyl chloride were the desired product,the catalyst system would consist of palladium chloride, ferric chlorideand sodium chloride. The reaction is conducted at a temperature in therange of between 350 and 650 F. In accordance with the process of theinstant invention, monohalogenated olefins such as vinyl chloride can bereadily obtained at high selectivities and correspondingly goodconversion levels.

DESCRIPTION OF THE PRIOR ART y The reaction of olefins, such asethylene, propylene, butylenes and the like, with a catalyst comprisedof a compound of a platinumgroup metal and a halide of a metalpossessing a variable valence to form halogenated hydrocarbons is old inthe art. In accordance with this process, the metal chloride is reducedto a lower state of valence (for example, cupric chloride to cuprouschloride), thereby yielding chlorine which saturates the double bond orbonds of the olefins. The reduced metal chloride may be regenerated,i.e. oxidized, by reacting it with hydrogen chloride and anoxygen-containing gas such as air. This oxidation step may be effectedeither simultaneously with the olefin halogenation step orintermittently therewith.

In U.S. Pat. No. 3,354,234, there is disclosed a process for themanufacture of halogenated hydrocarbons in substantial accordance withthe above-described procedure. Specifically, a gaseous mixturecomprising an olefin, a hydrogen halide and a source of elemental oxygenis reacted vwith a supported catalyst consisting essentially of a halideof a platinum-group metal and a halide of a metal of variable valence,cupric chloride. However, the process disclosed in U.S. Pat. No.3,354,234 of reacting the olefin, hydrogen chloride and a source ofelemental oxygen with the claimed catalyst of a platinum-group metal anda halide of copper produces a wide range of halogenated hydrocarbons andorganic by-products. Such a process, while generally applicable to themanufacture of halogenated hydrocarbons, predominantly forms thedihalogenated-substituted olefins. For example, when ethylene is used asthe starting material in the process described in U.S. Pat. No.3,354,234, in addition to the formation of a monohalogenated olefin(vinyl chloride) the halogenated hydrocarbons that predominate includeethyl chloride, l,l-dichloroethylene, 1,1-di-chloroethane and 1,2-dichloroethane. Consequently, the art is in need of a process for theselective halogenation of an olefin (ethylene) to a monohalogenatedsubstituted olefin (vinyl chloride).

SUMMARY OF THE INVENTION It has now been discovered that monohalogenatedolefins such as vinyl chloride may be selectively prepared in highyields by employing a catalyst system containing a palladium metalhalide, a ferric halide wherein iron is in the oxidized state, and analkali metal halide such as sodium chloride. In accordance with theprocess of the present invention, a mixture consisting essentially ofanolefin, a hydrogen halide and a source of oxygen is contacted at atemperature in the range of between 350 and 650 F. with the catalystsystem claimed herein. In a preferred embodiment of this invention,vinyl chloride is produced in high selectivities and at good conversionlevels by reacting a mixture consisting essentially of ethylene,hydrogen chloride, and a source of oxygen at a temperature in the rangeof between 500 to 650 F. with a catalyst system containing palladiumchloride, ferric chloride and sodium chloride. In accordance with theinstant invention, it has been found that the use of copper, which isoften employed as the variable valence transition metal, (such as cupricchloride), must be avoided if high selectivities to the monohalogenatedolefin is to be achieved. Thus, in a preferred embodiment of thisinvention wherein vinyl chloride is selectively prepared at goodconversion levels, it has been found that a catalyst system containing,in addition to palladium chloride, ferric chloride in combination withan alkali metal halide such as sodium chloride selectively produces themonohalogenated olefin and prevents the formation of large amounts ofdichloroethylenes and/or ethylene dichloride. In addition, it has beendiscovered that the use of an alkali metal selected from the groupconsisting of sodium and potassium in the presence of a palladiumchloride and ferric chloride catalyst increases the conversion levels ofthe ethylene while maintaining high selectivities to the monohalogenatedolefins (vinyl chloride). The halide of the alkali metal employedcorresponds to the desired halogenated hydrocarbon formed. For example,in the process for the selective formation of vinyl chloride, the sodiumor potassium is employed as the chloride.

The selective nature of this catalyst system claimed herein is of greateconomic importance since monohalogenated olefins such as vinyl chloridehave many valuable uses not shared by the disubstituted halogenatedolefins. In recent years, these monohalogenated olefins, especiallyvinyl chloride, have become important and valuable commercial products.Thus, the art has been in need of a one-step process for the selectiveformation of monohalogenated monomers such as vinyl chloride. Thesemonomers are particularly valuable commercial products in view of thefact that they are valuable precursors for polymeric materials.

The olefins which may be employed in the practice of this inventioninclude straight and branched-chain monoolefins, monoolefins containinga cyclic group, monoolefins containing an aryl group and diolefinscontaining any of the abovementioned groups. The olefins or diolefinscan have from 2 to about 12 carbon atoms. Representative, nonlimitingexamples are as follows: ethylene, propylene, l-butene, 2-butene, butadiene, isobutylene, l-pentane, l-hexene, Z-heptene, l-octene,2-nonene, 4-dodecene, cyclohexene, methylene cyclohexane, vinylcyclohexane, divinyl cyclohexane, styrene, di-vinyl benzene, alphamethylstyrene, beta ethylstyrene, vinyl naphthalene, and the like.

The use of palladium as the platinum group metal" is a critical featureof the instant invention. It has been found that palladium must beemployed in conjunction with a ferric halide and an alkali metal halideselected from the group consisting of sodium and potassium in order toselectively fonn the monohalogenated olefins. Palladium must be employedin the catalyst system of the instant invention to the exclusion of theother members of Group VIII of the Periodic Table, e.g. Ruthenium,Rhodium, Iridium and platinum. When palladium is employed in thecatalyst system of the instant invention, there is a preferentialvinylic substitution of the double bond to form the monohalogenatedolefin (vinyl chloride). The use of rhodium, ruthenium or iridium as theplatinum group metal does not exhibit such a selectivity to themonohalogenated olefin. In fact, the use of platinum results in theselective formation of the di-substituted olefin (ethylene dichloride).The halides employed in conjunction with the palladium metal correspondto the desired halogenated hydrocarbon to be formed. For example, wherethe desired monohalogenated olefin to be formed is vinyl chloride,palladium chloride would be employed as the platinum-group metal halide.

The source of oxygen may be any oxygen-containing gas stream, such asair, or pure oxygen can be used. The oxygen employed in the instantprocess varies from 10 mole percent to 200 mole percent based on theamount of starting olefin employed.

The halide of hydrogen employed in the practice of this inventioncorresponds to the desired monohalogenated olefin produced. This, whenvinyl chloride is formed in accordance with the instant invention,hydrogen chloride is employed as the hydrogen halide. The hydrogenhalide present in the reaction zone can vary from a molar ratio of about0.5:1 to about 10:1 of hydrogen halide to the starting olefin employedas the feed. Preferably, the molar ratio of hydrogen halide to theolefinic feed varies from about 2:1 to 5:1.

Generally, the reaction is conducted at a temperature in the range offrom about 350 to 650 F. Preferably, the reaction is conducted at atemperature in the range of from about 500 to 550 F. The reaction can beconducted at pressures ranging from about atmospheric to aboutatmospheres pressure and more preferably at about atmospheric pressure.

The use of iron in the oxidized state, as for example ferric chloride,as the variable valence transition metal, is a critical feature of theinstant invention. Heretofore, it has been believed that any variablevalence metal which, upon being reduced to a lower valence stateliberates a halide which then can saturate the double bond, may beemployed to manufacture a monohalogenated olefin. However, it has nowbeen discovered that in order to selectively prepare a monohalogenatedolefin at high selectivities with good conversion levels it is necessaryto employ iron as the variable valence transition metal. While notwishing to be bound to any particular theory, it is believed that theuse of a variable valence transitional metal which also can beclassified as a Deacon catalyst, Le. a metal salt that oxidizes HCl tochlorine such as cupric chloride, is to be avoided. For example, when aDeacon type catalyst such as copper is employed as the variable valencetransitional metal in accordance with the practice of the instantinvention, cupric chloride tends to dissociate according tstbsfsflwhsagit n 3 l s s sblsris 2 CuCl, 2 CuCl C1 This chlorine can thereafterchlorinate the starting olefin (such as ethylene in the formation ofvinyl chloride) to ethylene dichloride and can also lead to theformation of dichloroethylenes by free radical substitutive chlorinationof ethylene. The use of such a Deacon-type catalyst as the variablevalence transitional metal, therefore, decreases the selectivity to themonohalogenated olefins by increasing the selectivities to thedisubstituted halogenated olefins such as dichloroethylenes and/orethylene dichloride. Thus, in order to form the monohalogenated olefinsin high selectivities at good conversion levels, it is necessary toavoid the use of a Deacon type catalyst such as copper as the variablevalence transitional metal in the catalyst system of the instantinvention.

In addition, it has been discovered that the addition of an alkali metalhalide such as sodium chloride to the palladium chloride, ferricchloride catalyst system significantly increases the conversion as wellas the selectivity to the monohalogenated olefin product. For example,in the synthesis of vinyl chloride, the addition of sodium to thepalladium chloride, ferric chloride catalyst system increased theconversion of the starting ethylene feed from 7.1 percent conversionlevel to an 88.1 percent conversion level at 550 F. Correspondingly, asthe temperature was raised from 475 to 550 Pl. t he select ivity tovinyl chloride increased from 410 60.

2 percent. Thus, it can be seen that by employing iron in the oxidizedstate as the variable valence transition metal in combination with analkali metal in a platinum group metal halide variable valencetransition metal catalyst system, increased selectivities to themonohalogenated olefins at excellent conversion levels can be obtained.Furthermore, the addition of potassium in the alkali metal exhibits asignificant increase to the selective formation of monohalogenatedolefins.

The catalyst system of the instant invention may be supported on variousmaterials such as alumina, silica gel, silicaalurnina, silicon carbide,titania, zirconium silicate and the like, with alumina being thepreferred support material. The surface area of the support may varyfrom less than 1 square meter per gram to 200 square meters per gram,preferably from 1 to 50 m./g. and more preferably from 2 to 10 m.'/g.The support catalyst of the instant invention is amenable to a fixedbed, fluidized or moving bed operation.

The concentration of palladium on the support material may vary fromabout 0.1 to about 10 wt. percent and preferably from 0.5 to 5 wt.percent. The ferric and alkali metal concentrations on the support mayeach vary from about 0.3 to about 20 wt. percent, and preferably fromabout 0.5 to 2.0 wt. percent. Most preferably, the alkali metalconcentration varies between 0.2 and 1.0 wt. percent.

The molar ratio of the said gas comprising an olefin, e.g. ethylene,hydrogen halide, e.g. HCl, and oxygen (ethylene/HCl/0,0.5 to [.0 molesof oxygen and 2.0 to 3.0 moles of hydrogen halide per mole of olefin.The total feed gas space velocity can vary from about V/V/Hr. to about2,000 V/V/Hn, with a space velocity of about 1,000 V/V/Hr. beingpreferred.

An inert diluent such as nitrogen, helium, carbon dioxide and the likeand a saturated hydrocarbon such as ethane, propane and the like can beused in the practice of this invention if desired but the process canalso be practiced without the use of a diluent.

This invention will be further understood by reference to the followingexamples. In all of the Examples, the feed gases, ethylene, HCl andoxygen under mm. mercury pressure above atmospheric were passed into theheated reactor. The reactor was a 316 stainless steel tube 22 incheslong having an OD of one-half inch and was encased in an electricallyheated aluminum block. The reaction products were maintained in thevapor state and conducted to a heated gas sampling assembly attacheddirectly to a vapor phase chromatograph. A 6-foot Porpak Q columnprogrammed from 45 C. to 215 C. at 7.5 C/min. gave a combined peak forair and CO but separate peaks for CO ethylene, HCl, water, acetic acidand all of the chlorinated products. A 3-foot 5 Angstrom molecular sievecolumn at 45 was used to resolve the air-C0 peak into oxygen, nitrogenand CO.

The catalysts used in this study were prepared by coating Davisonalumina of surface area 3-6 mF/g. with the metal chlorides. The metalchlorides were dissolved in dilute hydrochloric acid, the alumina wasadded and the water evaporated under vacuum with a rotary evaporator.Prior to use the catalyst was heated in air at 500 F. for 2-3 hours.

EXAMPLE 1 This example indicates the high selectivity to po lychl orideTABLE I.CHLO RINATION OF ETHYLENE WITH A PALLADIUM-COPPE R- SODIUMCATALYST Catalyst: 1% Pd+1% Cu+l% Na on alumina (s.a.=3.0 m. /g.); totalspace veloclty=1,000

in n h chlorination f y n h n pp r i mmetal and sodium as the alkalimetal. The catalyst was P y as the Variable Valence transition metal.Sodium as the prepared by coating the carrier with the metal chlorides.The alkali metal and palladium as the platinum group metal. As metalchlorides were dissolved in dilute hydrochloric acid, the can be Seenfrom the results as tabulated in Table the concatalyst carrier was addedand the water evaporated under r i Of ethy e Was 87.0 p en at 5 vacuumwith a rotary evaporator. Prior to use the catalyst was However, theselectivity of vinyl chloride at this conversion heated in air at 500 F.for 2 to 3 hours.

level was only 7.8 percent as there was approximately an 82.1 As can beseen from the results in Table III, as the temperapercent selectivity toethylene dichloride with a selectivity to ture was raised from 500 to550 F the ethylene conversion the heavier chlorides such asdichloroethylenes a d increased from 49.4 to 88.1 percent. This is ahigh conversion trichloroethane of 9.4 percent. As mentioned above, thehigh level increase in view of the ethylene conversion which takesselectivities to dichloroethylenes and/QI h l gj m place when aplatinum-group metal, that is palladium, and a when copperis employed inthe platinum-group metal, variavariable valence transition metal otherthan copper, that is ble valence transitional metal catalyst system, canbe exis p y solely as the catalyst system- For in plained by the factthat copper i a Deacon catalyst, Th the parison with the conversionlevels as shown in Example 2, the use of copper in the platinum-groupmetal-variable valen ethylene conversion level increased from only 3.5to 7.1 pertransition metal-catalyst system must b id d if cent over thesame temperature range (500 to 550 F.) when monohalogenated olefins,e.g. vinyl chloride, are to be formed the Catalyst System consisted ofthe p p metal at high selectivity at good conversion levels without asimuland the Variable Valence transition metal other than PP taneousproduction of large amounts of heavier chlorides. addition, theSelectivity to f y Chloride the l' t range of 500 to 550 F. using thepalladium, femc, sodium EXAMPLE 2 catalyst system was between 52.8 and60.2 percent in the ex- (1 temperature range. In addition, in contrastto the The effect when a variable valence transition metal other amine 1than copper is employed in the platinum-group metal-variable resultsobtained when copper was employed as a vanab e valence transition metalthe selectivity to higher chlorides valence transition metal catalystsystem 15 examined in Table d t i tem was on] 5.0 ercent ll. iron 18employed as the variable valence transition metal wlth the Instantlyclalme Ca a yst Sys y p and palladium as the platinum-group metal. Ascan be seen g! 500 m from the results tabulated in Table I], as thetemperature is raised from 500 F. to 600 F. the selectivity to vinylchloride 7 V i W A W A rose from 29.7 percent at 500 F. with a 3.5percent ethylene a M 7 conversion to 44.9 percent at 600 F. with acorresponding This example indicates the effect of the use of potassiumas 41.5 percent ethylene conversion. However, it should be the alkalimetal, palladium'as the platinum-group metal and noted that as thetemperature was raised from 500 F. to 600 iron as the variablqvalence{{{HEQJIEQLAQFQQ P2 359 TABLE III.CHLORINATION OF ETHYLENE WITH APALLADIUM-IRON SODIUM CATALYST Catalyst: 1% Pd+1% Fe+1% Na on alumina(s.a.=5.5 m. /g.); total space velocity=1,000

v./v./hr.; C2H|[HCl/Og=1/3/1 Ethylene Selectivity, mole percentconversion Vinyl Ethyl Dichloropercent chloride chloride ethylene EDCCO+CO HoAc F., the selectivity to ethyl chloride decreased from 61.9perfrom the results shown in Table IV, as the temperature was cent to8.6 percent while the selectivity to heavier chlorides raised from 500to 550 F. the ethylene conversion increased remains rQm. ..-0 @0525 pece t h s sa re a i a sseteei a TABLE II.CHLORINATION OF ETHYLENE WITH APALLADIUM-IRON CATALYST Catalyst: 1% Pd+1% Fe on alumina (s.a.=3.3m./g.); total space velocity=1,000 v./v./hr.;

CzH4/HCl/O =1/3/1 Ethylene Selectivity, mole percent conversion, VinylEthyl Poly- Temp., F. percent chloride chloride chloride EDC CO+CO2EXAMPLE 3 5 level increase as compared to that found with thepalladiumiron catalyst. In comparison, the conversion levels as shown inThis example indicates the effect of the addition of an alkali Example2, increased from only percent to 7 percent metal to theplatinum-group-variable valence transition metal over the temperaturerange (5000 to R). The selectivity catalyst system in the absence ofemploying copper as the varito ethyl chloride in the temperature range 00 R using able valence transition metal. Iron was employed as thevariathe palladium, ferric, potassium catalyst was i h an e of blevalence n iti n E l? l?? l? s! aws s 36.0 to 49.5 percent.

TABLE IV.CHLORINATION OF ETHYLENE WITH A PALLADIUM-IRON- POTASSIUMCATALYST Catalyst: 1% Pd+1% Fe+1% K on alumina (s.a.=5.5 m.'/g.); totalspace veloeity=1,000

v.lv.[l1r.; C;H4/HCl/O 1/3/1 Ethylene Selectivity, mole percent COIIVGT-slon, Vinyl Eth l Poly- Temp., F percent chloride chlori e chloride EDCCO+CO2 EXAMPLE 5 EXAMPLE 7 This example shows the results obtained inthe chlorination This example shows the results obtained in thechlorination of ethylene to vinyl chloride using ruthenium as theplatinumof ethylene to vinyl chloride using iridium as the platinumgroupmetal, iron as the variable valence metal and sodium as group catalyst,iron as the variable valence metal and sodium the alkali metal. As canbe seen from Table V, when the temas the alkali metal. As can be seenfrom the results of Table perature was raised from 450 to 600 F. theethylene conver- Vll, when the temperature was increased from 450 to 600F. sion increased from 12.9 to 65.3 percent whereas the selectivithe ethlene conversion increased from 9.9 to 26.7 percent ty to vinyl chlorideincreased from 1 Li percent to 25.6 per ent- TABLE V.CHLORINATION OFETHYLENE SODIUM CATALY while the selectivity to vinyl chloride increasedfrom 2.1 to 38.3 percent.

SYlIZITH A RUTHENIUM-IRON- Catalyst: 1% Ru+1% Fe+1% Na on alumina(s.p.=5.5 mJ/gJ; total space veloelty=1,000

Selectivity, mole percent Ethylene con- Diversion, Vinyl Eth l chloro-Temp., F. percent chloride chlori e ethylene EDC 00-1-00:

TABLE VIL-CHLORINA'IION OF ETHYLENE WITH AN IRIDIUM-IRON- N SODLUMc'lTALYgT to] i it 1 000 Catalyst: 17 Ir 1? Fe+17 a on umina s.a.=5. In.g. ;to space ve oc y= 0 v.lv./hr.; 0.H./Hc1 o.=1/a/1 EthyleneSelectivity, mole percent conver- Ethyl Polychloride chloride EDC CO+COEXAMPLE 6 EXAMPLE 8 This example shows the results obtained in thechlorination of ethylene to vinyl chloride using rhodium as theplatinumgroup catalyst, iron as the variable valence metal and sodium asthe alkali metal. As can be seen from the results in Table VI, theethylene conversion increased from 31.9 percent at 450 F. to 77.2percent at 600 F. The vinyl chloride selectivity increased from 12.9 to20.6 percent.

TABLE VI.CHLORINATION SODIUM CATALYST OF ETHYLENE WITH A RHODIUM-IRON-Catalyst: 1% Rh+1% Fe+1% Na on alumina (s.a.=5.5 m."lg.); total spacevelocity=1,000

Selectivity, mole percent 9 10 from 71.9 to 80.8 percent. In this sametemperature range. the EXAMPLE l selectivity to vinyl chloride was 12.5to 14.1 percent. in cona trast to use of palladium in the catalystsystem as shown in Ex- This example shows the results obtained byvarying both the ample 2, the use of platinum favors the selectiveformation of sodium and iron concentrations in the catalyst wherepalladithe ii-Su stitut d l fin thyl n di hl rid um is the platinumgroup metal, iron the variable valence TABLE X.EFFECT OF IRON AND SODIUMCONCENTRATION ON THE CHLORINATION OF ETHYLENE Catalyst: 17 Pd+X7 Fe-i-XVNa on alumina (s.a.==5.5 m. total space velocity=l000v./v. r.-

o o o OgH/HC1/02 /3/ /8 1 I I Ethylene Selectivity, mole percent conver-P l n, yl Iron and sodium, percent Temp.,F. percent chloride chloridechlori e EDC CO+C0,

TABLE VIIL-CHLORINATION OF ETHYLENE WITH A PLATIN UM-IRON- SODIUMCATALYST Catalyst: 1% Pt+1% Fe+1% Na on alumina (s.a.=5.5 m. /g.); totalspace veloclty=l,000

v./v./hr.; C:H4/HC1/Oz=1/3/1 Selectivity mole rcent Ethylene pe Con-Diversion, Vinyl Ethyl ch1or0- Temp, F. percent chloride chlorideethylene EDC CO+CO EXAMPLE 9 ,metal and sodium the alkali metal. Theresults obtained from This example shows the effect of varying sodiumconcentracatalysis Whlch the and Sodium concentrations ranged tlon inthe catalyst where palladium is the platinum-group 5 from 0.25 Wt.percent 10 4.0 Wt. percent at a 1 percent palladimetal d i i h i blvalence l, Th ff f um level are shown in Table X. At a fixedtemperature, the

varying the sodium concentration from 0.21 to 1.6 percent at selec ivityto burning was quite high at 0.25 percent Fe and Na a lpercent Pd and 1percent Fe level is shown in Table IX. As but h n d ppe as the i contentwas increased.

can be seen from the last column o f the tab1e w hen the sodium reachinga minimum at about 1 percent Fe-Na. The selectivity concentration wasincreased from 0.21 to 1 percent the seleco bu ning beg n o ncre se agaias the Fe-Na concent ation tivity to burning decreased significantly atthe same t was increased to 2 and 4 percent. At a given temperature, thetrue. Howe er when more sodium was added (1.6 percent) ethyleneconversion increased as the Na-Fe content was inthe selectivity tobuming increased to a high level. The opcreased but the highestselectivity to vinyl chloride was found timum sodium concentration forminimum burning w thu 1 at a 1 percent level of Fe-Na. The highestselectivity to vinyl percent. This sodium concentration also gave the hih chloride (60.2 percent at 550 F.) at a high ethylene converselectivityto vinyl chloride (60.2 percent) at 550 F. at an 'sion (88.1 percent)was found for the 1 percent Pd, 1 percent ethylene conversion of 88.1percent. EE PEE PEEEQQQEF TABLE IX.-EFFECT OF SODIUM CONCENTRATION ONTHE CHLORINATION OF ETHYLENE Catalyst: 1% Pd+1% Fe+X% Na on alumina(s.a.=5.5 m.=/g.); total space velocity =1,000 v./v./hr.;

CzH|/HCl/O2=1/3/1 Ethylene Selectivity, mole percent conversion, VinylEthyl Poly- Sodium, percent 'Iemp., F. percent chloride chloridechloride EDC CO+CO2 EXAMPLE it This example shows the results obtainedby varying the oxygen concentration with a 1 percent palladium-l percentironl percent sodium catalyst. As can be seen in Table XI as the EM LEl3 As can be seen from Table XIII, the use of iron in the oxidized state(ferric iron) in the catalyst system of the instant invention is uniquein obtaining high conversion in high selecchloride when sodium orpotassium is added to the catalyst system of the instant invention. Ascan be seen from Table Xll. sodium and potassium are unique in achievinghigh conversion levels and selectivities to vinyl chloride.

XIL-OXYCIILORINA'IION OF ETHYLENE WITH N ACTIVATED PALLADIUM-IRONCATALYST Ethylene Conversion (Mole percent) Catalyst: 1% of each metal(as chloride) on alumina (s.a.=5.l m. /g.);

C2H|IHCl/Oz=l/3/1; total space velocity=i,000 v./v.[l1r.

Temperature, F.

TAB LE A Catalyst oven Pd+Fe+Na Selectivity to Vinyl Chloride (Molepercent) Catalyst: 1% of each metal on alumina (s.a.=5.6 m. /g.);CzElt/HCl/Oz= 113/1; total space velocity=1,000 v./v./hr.

Temperature, F.

Catalyst 450 500 550 600 Pd+Fe 22 52 45 Pd-l-Fe-l-Mg 23 33 b2 Pd+Fe+Ca.65 70 79 Pd+Fe+Ba 24 49 66 28 Pd+Fe+Pb 7 19 54 64 Pd+Fe+Bi 15 22 36 54Pd+Fe+Li- 14 2A 31 Pd+Fe+Zn 12 27 49 26 Pd+Fe+Ag- 39 42 68 24 Pd+Fe+K 2539 54 57 Pd+Fe+Na 53 *Chlorldes of the metals were used in all catalystpreparations.

was

molar ratio of oxygen is raised from 0.5 to 0.75 to L0 the ttvtty tovinyl chloride. ethylene conversion at a given temperature is notaffected siga mficantly over the temperature range 475 to 525 F.Similarly TABLE XIHPOXYCHLORINATION OF ETHYLENE WITH the selectivitresto the various products, particularly vinyl A PALLADIUM-SODIUM PLUSMETALS CATALYST chloride and EDC, are not affected. Only at 550 F. isthere an Ethyleng conversions (M010 percent) increase in ethyleneconversion from 63.9 percent at 0.5 Catalyst: 1% or each metal onalumina (s.a.==5.5 ins/ 7 total space moles oxygen to 85.5 percent at0.75 moles oxygen but as the velmnyflimo CHIHCVOFUS oxygen ratio isincreased further to l .0 there is only a small ad- Temperature. 1-.dmonal increase 1n ethylene conversion to 88.1 percent. at Catalyst""15""? 3;, lower temperatures, the selectivity to vinyl chlorideremained l 5 relatively constant (59.8-60.2 percent) while theselectivity to -1 EDC increased slightly from 21.2 to 25.2 percent. 13go-Ng V I; I: (to 0. 7 12;! 2.1

TABLE XL-EFFECT 0F OXYGEN CONCENTRATION (AT 3 MOLES HCl/MOLE ETHYLEN E)ON THE CHLORINATION 0F ETHYLENE Catalyst: 1% Pd+1% Fe+l% Na on alumina(s.a.=3.3 mJ/g); total space velocity 1,000 v./v./hr.; C2H4/HCl/Og=1/3/XSelectivity, mole percent Ethylene conversion, Vinyl Eth l Poly- MclesOz/Mole 0 H; Temp, F. percent chloride chlorl e chloride HoAc EDC00-1-00,

475 37. 6 43. 5 2B. 0 7. 6 3. 7 16. 3 0. 9 0 5 500 46. 9 51. 4 l8. 0 5.0 5.1 20.0 0. 5 52B 61. 5 57. 2 l0. 3 3. 4 7. 9 20. 4 0. 8 550 63. 9 60.2 5. 8 3. 5 7. 9 21. 2 l. 4 476 36. 1 4b. 8 26. 3 7. 4 4. 2 l6. 7 0. 6M6 500 49. 7 54. 5 14. s 4.6 5. 0 19.8 0. 4 52B 64. 6 55. 7 9. 0 3. l 7.l) 23. 6 0. 8 M0 85. 6 59. ll 3. 8 2. 8 7. 7 23. 4 2. 6 475 87. a 47. 423. 0 7. 3 4. 0 17. 7 0. u 1 0 500 40. 4 52. s 14. 7 5. 0 a 4 21. s 0. 5f 625 66. 8 Eli. 1 8. 4 3. 2 7. 2 24. 4 0.7 I 560 88. 1 60. 2 3. 1 2. 36. 4 25. 2 2. 8

EXAMPLE 12 D H 35 Pd-Nt-sa 0.4 0.6 0.8 1.6 Pd-Ag-Na. 0. 3 0. 2 0. 2 0. 2This example shows the unexpected and significant increase ggjgg i 3;:8:8 2:? in the conversion level of ethylene and selectivity to vinylPd-Oe-Ns. 0. 6 0.4 0 3 Pd-Fe-Na 49. 4 S8. 1

Selectivity to Vinyl Chloride (Mole percent) Catalyst: 1% 01 each metalon alumina (s.a.==ll.5 IILZ/FJ; total space velocity=1,000 v./v./hr.;CzHt/HC1IO1=1/3 1 Temperature, F.

Catalyst 450 500 550 600 Pd-Cr-Na 46 71 74 Pd-Mn-Na. 23 31 34 38 Pd-C0Na22 39 56 51 Pd-Nl-Na 57 71 80 61 so Pd-Ag-Na 82 B7 62 41 Pd-W-Na. 35 2942 45 Pcl-Pt-Na. 13 25 40 Pd-Ce-Na- 54 77 77 80 Pd-Fe-Na 53 60 Glassreactor in molten solder bath was used.

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l. A process far the formation of vinyl chloride which comprisescontacting at a temperature in the range of from about 500 to 550 F. amixture of ethylene, hydrogen chloride and oxygen with a catalyst systemconsisting of palladium chloride. ferric chloride and an alkali metalchloride wherein the alkali metal is selected from the group consistingof sodium and potassium wherein the amount of palladium in said catalystsystem is in the range of from about 0.5 to 5 weight percent and whereinthe amount of ferric and alkali metal employed in said catalyst systemvaries from about 0.5 to about 2 weight percent.

2. The process of claim 1 wherein the alkali metal is sodium.

3. A process for the formation of vinyl chloride which comprisescontacting at a temperature in the range of from about 500 to 550 F. agaseous mixture consisting essentially of ethylene, hydrogen chlorideand oxygen with a supported catalyst, said catalyst consisting ofpalladium chloride, ferric chloride and sodium chloride wherein theconcentration oi 5. The process of claim 3 wherein said support isalumina.

6. The process of claim 5 wherein the amount of palladium employed insaid catalyst system is in the range of about 1 weight percent, whereinthe amount of ferric chloride is in the range of about 1 weight percentand wherein the amount of alkali metal employed in said catalyst systemis in the range of about 1 weight percent.

2. The process of claim 1 wherein the alkali metal is sodium.
 3. Aprocess for the formation of vinyl chloride which comprises contactingat a temperature in the range of from about 500* to 550* F. a gaseousmixture consisting essentially of ethylene, hydrogen chloride and oxygenwith a supported catalyst, said catalyst consisting of palladiumchloride, ferric chloride and sodium chloride wherein the concentrationof palladium on the support is in the range of from about 0.5 to about5.0 weight percent and wherein the ferric and sodium concentration onthe support may each vary from about 0.5 to about 2.0 weight percent. 4.The process of claim 3 wherein the molar ratio of the gaseous mixtureconsisting essentially of ethylene, hydrogen chloride and oxygen isabout 0.5 to 1.0 moles of oxygen per mole of ethylene and about 2.0 toabout 3.0 moles of hydrogen chloride per mole of ethylene.
 5. Theprocess of claim 3 wherein said support is alumina.
 6. The process ofclaim 5 wherein the amount of palladium employed in said catalyst systemis in the range of about 1 weight percent, wherein the amount of ferricchloride is in the range of about 1 weight percent and wherein theamount of alkali metal employed in said catalyst system is in the rangeof about 1 weight percent.